Rare NPE crash in ActivityLogListFragment 

```
Caused by kotlin.TypeCastException: null cannot be cast to non-null type org.wordpress.android.fluxc.model.SiteModel at 
org.wordpress.android.ui.activitylog.list.ActivityLogListFragment.onViewCreated(ActivityLogListFragment.kt:57)
```

5ba662b6f8b88c2963e156c0-fabric